Popcorn

Popcorn is produced from a specific variety of maize called Zea mays everta, a flint corn grown specifically because its kernels pop rather than merely parch when heated. Each kernel holds a small amount of moisture and oil inside a hard, moisture-resistant hull; as the kernel heats, the trapped water turns to steam and pressure builds until the hull ruptures, instantly expanding the starchy interior into a light foam many times the kernel's original size. Archaeological evidence places popped corn among the oldest snack foods, with remains found in Peru dating back roughly 4,700 years, and the snack's modern popularity in the United States took off after Charles Cretors invented a steam-powered popcorn machine in Chicago in the 1890s.